阳离子色谱法在VVER机组一回路水质分析中的优化应用

Optimization and Application of Cationic Chromatography in Analysing Core Coolant of VVER

田湾核电站一回路样品中的阳离子主要包括NH^(+)_(4)、K^(+)、Na^(+)、Li^(+)(即总碱金属)。在冷却剂中加入氨水,可使其间接辐照分解产生氢气来维持一回路冷却剂的还原性,总碱金属含量的控制是为了维持核电站一回路冷却剂弱碱性环境,有效降低系统腐蚀速率,所以阳离子的准确测量对机组的安全具有重要的意义。一回路阳离子测量一般采用分光光度法和原子吸收法,但传统的测量方法步骤繁琐、分析耗时长。为此,采用离子色谱对田湾二期样品特性测量条件进行优化,实现阳离子的准确快速测量。结果表明测量的相对标准偏差为0.02%~0.15%,回收率为98.8%~105.0%,4种阳离子测量平均耗时28 min。该方法具有人为引入误差小、操作简单、分析快速等特点。

The cations in core coolant of the Tianwan Nuclear Power Plant mainly include ammonium ions,potassium ions,sodium ions and lithium ions.Adding ammonia to the coolant can decompose it by indirect irradiation to produce hydrogen to maintain the reducibility of the core coolant.The purpose of controlling total alkali metal content is to maintain the weak alkaline environment of the core coolant and effectively reduce the corrosion rate of the system.Therefore,accurate measurement of cationic ions is of great significance to the safety of the nuclear power plant.The determination ofcationcontent in core coolant is conventionally performed by means of spectrophotometry and atomic absorption,which are cumbersome and time-consuming.This paper uses chromatography to optimize measurement conditions in consideration of characteristics of core coolant,realizing accurate and rapid measurement of cations.The results show that the relative standard deviations are 0.02%~0.15%,the recovery rate is 98.8%~105.0%,and the average cation measurement time is 28 min.This method has fewer interference factors of person and is convenient and fast.